Traditional wood based home building techniques typically include the use of stick lumber, sheeting, beams, trusses, engineered lumber products and other components fashioned from wood in the form of lumber or laminated elements. Consequently the demand for wood is high requiring harvesting rates often exceeding the replenishment rates. Timber bamboo, being a grass, is prolific throughout the world and as a construction material has many advantages over wood including material cost, strength, rapid growth, high carbon sequestration and sustainability making timber bamboo an attractive substitute for wood. Use of timber bamboo as a wood replacement is highly desirable; however, the dimensional format of timber bamboo limits the use as a direct substitute.
The longitudinal compression strength of timber bamboo is largely attributed to the orientation of fibers running longitudinally within the culm. The fiber orientation is principally parallel with the exception of some cross fibers in the nodal regions. As typical of plant material, the fibers are bound together with lignin. Although the fiber orientation contributes to the high compression characteristics of a bamboo cane making whole culm bamboo canes well suited for applications such as scaffolding and columns or posts. In longitudinal sheer the load performance of bamboo is reduced by the parallel fiber arrangement. Failure modes of bamboo cane in sheer typically include splitting along the length of the culm wherein the parallel fibers separate. Such a failure mode is also evident when fasteners such as bolts are disposed through the culm resulting in poor pull out performance in sheer along the grain making the use of nature bamboo a poor substitute for wood that comprises additional cross fibers.
Natural bamboo cane, being tubular in shape, has a limited number of applications as a construction material, particularly in western style construction. In order to fabricate traditional dimensional construction material, such as lumber and beams, the bamboo culm is typically processed and formed by shredding, chipping or milling into elements that are recombined as a composite material using resins that can be manipulated and formed into dimensional lumber sized pieces. The processes disrupt or destroy the natural fiber orientation and lignin bonds and therefore the natural strength characteristics of the bamboo cane typically resulting in materials exhibiting lower strength characteristics and heavier weights than the natural bamboo cane. Forming dimensional construction material from bamboo with minimal disruption of the natural bamboo culm maximizes the utilization of the natural bamboo characteristics; however, bamboo culm is typically thin walled thereby limiting the opportunities for cutting dimension construction elements directly from the bamboo culm.
Therefore, what is needed is a bamboo alternative to wood based dimensional lumber and engineered lumber products providing structural characteristics meeting or exceeding wood based products while being sustainable and renewable. In particular, a bamboo lumber and method of manufacturing is needed overcoming disadvantages of tubular bamboo cane and having dimensions equivalent to traditional lumber components, structural characteristics meeting or exceeding wood components, while also being cost efficient thereby providing a direct substitute for traditional wood based components.